Closed captions and/or subtitles are captions, typically in text form, that are contained in a video signal such as a video signal of a television program, movie, media file, or other audiovisual program. For example, text corresponding to dialogue, sound effects, and the like of an audiovisual program are transmitted with the video and audio information from a broadcaster or like content provider. Recovery of closed captions and subtitles for display along with the video typically requires a decoder or like device that enables the captions to be displayed in proper sequence on the display screen with the video of the program such that the captions or subtitles are temporarily superimposed on the video. The apparatus in which the decoder or like device is implemented, for instance, may include a set-top box, a television, a computer (desktop, laptop, tablet, pad, etc.), a video recorder or player, a hand held cellular telephone, or like electronic media player or device associated with a display.
There are various industry standards and specifications with respect to transmitting and rendering caption and subtitle information for being superimposed on a video. The standards and specifications typically specify how the subtitle/caption information is parsed, synchronized with the video, and positioned on the display screen.
By way of example, the EIA-608 standard is a standard for the delivery of closed captions developed by the Federal Communications Commission (FCC) with assistance from the Electronic Industries Association (EIA) Television Data Systems Subcommittee and is based on the Line 21 system utilizing the DVS-157 standard for carriage format in digital cable systems. The DVS-157 standard is a standard established for the cable industry by the Digital Video Subcommittee (DVS) of the Society of Cable Telecommunications Engineers (“SCTE”).
The more recently developed EIA-708 standard utilizes the carriage format specified in the Advanced Television System Committee's (ATSC) A/53 standard for digital video. The EIA-708 standard provides advanced closed caption features for digital television signals at the closed captioning origination device. The EIA-708 features include, but are not limited to, the ability to change certain closed caption features, such as the location of the closed caption display and the size and color of the closed caption text. With respect to standards for subtitles, DVB Subtitle rendering is specified in ETSI 300 743 and ARIB Subtitle rendering is specified in ARIB STD-B24. Similar specifications are provided for various other video formats including DVD and DivX formats.
A problem often experienced by a viewer of a video having subtitles or closed captions is that the subtitles/captions are not always provided in a manner that is convenient to the viewer with respect to readability of the subtitles/captions. For instance, the amount of subtitle/caption text displayed on a screen in a given amount of time varies greatly due to the variation in amount and rate of dialogue in the video and the pace and tempo of the dialogue in any particular scene or segment of the video. Subtitles and captions are displayed only for a limited amount of time before being removed and replaced with the next subtitle/caption in sequence. This is true regardless of the amount and/or rate of dialogue in a given segment of the video and may limit the viewer's ability to fully read each subtitle or closed caption, particularly when the dialogue of a particular segment of the video is intensive. By way of example, a first video segment may contain several long sentences of text in which the caption momentarily flashes on the screen and may be followed by another video segment that may contain very little dialogue, such as a single word. In this case, a viewer may be unable to read the entire caption with respect to the first video segment while having spare time in the following video segment.